438 DESCRIPTION OF SOME SPECIES OF MILK BACTERIA 



MICROCOCCUS ACIDI LAOTIS, 

 Nos. 1, 2, and 8 (Marpmann and Conn). 



Source and habitat — Milk. 

 Morphology — Coccus ; -6 to -8 ," in 



diameter. 

 Grouping — Occurs in masses. 

 Staining reaction — Ordinary aniline 



dyes. 

 Biology : cultural characters {includ- 

 ing biochemical features). 



Gelatine plates and tubes — Finely 

 granular round colonies with smooth 

 edge. In stab-culture moderate 

 "needle growth," rough and beaded. 

 Surface growth, rough, irregular, 

 and thick. No. 3, yellow at first, 

 becoming white. 



Agar plates and tubes — A white 

 growth becoming yellow. 



Potato — White, thick, spreading 

 growth which becomes yellow. No. 

 3 grows very abundantly, thickly, 

 and of a flesh colour. 



Milk — Rendered acid at 20° C. 

 but not curdled except at 35° C. 

 Cream is thickened and rendered 

 acid. Makes butter of good flavour. 

 Aerobic — A facultative anae- 

 robe. 

 Non-pathogenic. 



MICROCOCCUS ARBORBSCBNS 

 LACTIS (Conn). 



Source and habitat — Milk. 



Morphology — Coccus ; -7 /(* in di- 

 ameter ; singly, not in chains. 



Staining reaction — Ordinary aniline 

 stains. 



Biology : cultural characters {includ- 

 ing biochemical features). 



Bouillon — A very tough tena- 

 cious scum is formed. 



Gelatine plates and tubes — Deep 

 colonies are irregular, granular, 

 with a broken edge. In stab-cul- 

 ture growth along needle track 

 possesses radiating fibres. Surface 



growth white, not thick, but spreads 

 over surface. 



Agar plates and tubes ; potato — 

 Not characteristic, 



Aerobic. 



Non-pathogenic. 



MICROCOCCUS AUREUS LACTIS 



(Conn). 



Source and habitat — Milk. 

 Morphology — Coccus ; -8 /* in diameter ; 



in pairs or clumps. 

 Staining reaction — Ordinary stains. 

 Biology : cultural characters {includ- 

 ing biochemical features). 



Gelatine plates and tubes — Round 

 opaque colony with granular halo ; 

 liquefaction. In stab-culture a 

 shallow pit is produced which 

 deepens into a horizontal layer with 

 a yellow sediment. 



Agar plates and tubes : potato — 

 An abundant, moist, glistening, 

 yellow growth. 



Milk — Curdled and alkaline after 

 3 weeks. 

 Aerobic. 

 Non-pathogenic. 



MICROCOCCUS CANDICANS 



(Fliigge). 



Source and habitat — Common in air, 

 water, milk ; also occurs in human 

 hair. 



Morphology — Round cocci, singly or 

 in branches ; i-2 m in diameter. 

 Sometimes showing a dividing line 

 in centre. 



Staining reaction — Ordinary aniline 

 stains. 



Biology : cultural characters {includ- 

 ing biochemical features) — Grows 

 at room and blood temperature on 

 ordinary media. 



Bouillon — Cloudy growth with 

 some sediment ; pellicle forms. 



Gelatine plates and tubes — Round 

 colonies, 2 to 3 /* in diameter ; in 8 



